This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. xc2xa7119 from my application POWER CONTROLLING SYSTEM AND METHOD FOR DISPLAY filed with the Korean Industrial Property Office on Dec. 7, 2000 and there duly assigned Serial No. 83360/2000.
1. Technical Field
The present invention relates, in general, to a power control system and method for a display apparatus and, more particularly, to a power control system and method for a display apparatus wherein voltage applied to a switch unit for switching a reactor is cut off in an off mode, thereby reducing power consumption in the off mode.
2. Related Art
A typical power control system for a display apparatus includes a reactor provided with a pair of inductors, a switch unit connecting the inductors of the reactor with each other in either series or in parallel, a rectifier for rectifying AC voltage, a power supply for supplying the rectified voltage to various components of the apparatus, a voltage detector for detecting voltage between the rectifier and the power supply, and for supplying driving power to the switch unit, and a microcomputer for controlling a display power management system (DPMS).
The DPMS reduces power consumption when the display apparatus has not been in use for a certain period of time. The typical DPMS has several modes: an on mode, a stand-by mode, a suspension mode, and an off mode. Each mode is preprogrammed for a certain maximum power consumption. For example, the stand-by mode is set for about 80 W, the suspension mode is set for about 15 W, and the off mode is set for about 3 W.
When the DPMS enters the off mode, the microcomputer cuts off the output of vertical and horizontal synchronizing signals, and also cuts off power supply to each component of the display apparatus, as well as to the vertical and horizontal deflection circuits. However, when 220V is applied to the power control system, driving power is steadily supplied to the switch unit. As a result, power of 3.6 W is consumed, and that exceeds the maximum power consumption (3 W) preprogrammed for the off mode. This causes the excessive consumption of power, and defeats the purpose of the DPMS.
Therefore, there is a need for a power control system and method for a display apparatus in which driving power is not steadily supplied to the switch unit when 220V is applied to the power control system.
The following documents are considered to be generally pertinent to the invention disclosed and claimed herein, but are burdened by the disadvantages set forth above: Japanese Patent No. 08-98405 to Maekawa, entitled ACTIVE FILTER DEVICE, published on Apr. 12, 1996, Japanese Patent No. 08-308236 to Yasumura, entitled SWITCHING POWER SOURCE CIRCUIT, published on Nov. 22, 1996, Japanese Patent No. 08-237859 to Miyagi, entitled POWER SOURCE CIRCUIT FOR A ELECTRONIC DEVICE, published on Sep. 13, 1996, Japanese Patent No. 08-331846 to Yatori, entitled POWER SOURCE DEVICE, published on Dec. 13, 1996, Japanese Patent No. 11-27943 to Sato et al., entitled POWER SOURCE DEVICE, published on Jan. 29, 1999, Japanese Patent No. 10-191638 to Uchibori, entitled SWITCHING POWER SUPPLY DEVICE, published on Jul. 21, 1998, Japanese Patent No. 10-304660 to Aoki, entitled POWER SUPPLY CONTROLLER, published on Nov. 13, 1998, and U.S. Pat. No. 5,170,096 to Kang et al., entitled DEGAUSSING CIRCUIT USING A RELAY, issued on Dec. 8, 1992.
Accordingly, the present invention has been developed while keeping in mind the above-described problem, and it is an object of the present invention to provide a power control system and method for a display apparatus wherein power supplied to a switch unit for switching a reactor in an off mode is cut off, thereby reducing the power consumption in the off mode.
These and other objects of the present invention are accomplished by provision of a power control system for a display apparatus, comprising: a reactor, including a pair of inductors, for calibrating a power factor of an AC voltage externally supplied; a rectifier for rectifying the AC voltage having the power factor calibrated by the reactor; a power supply for outputting the rectified voltage with a plurality of voltage levels so as to allow them to be supplied to a power-consuming component; a switch unit for connecting the pair of inductors in the reactor in series or in parallel based on a driving power according to the levels of the AC voltage supplied to the reactor; and a microcomputer for determining whether a DPMS is in an off mode so as to cut off power supply to the component, and to cut off the power supply to the switch unit if it is in the off mode.
The power control system further comprises a voltage detection output circuit connected to one of the output terminals of a power supply for detecting the voltage level outputted by the power supply.
Preferably, the power control system further comprises an off mode switch connected to the other output terminal of the power supply for cutting off the power outputted by the power supply in the off mode.
The switch unit comprises a pair of three-contact relay switches and a driving coil for driving the relay switches. One end of the driving coil is connected to the off mode switch and the other end thereof is connected to the voltage detection output circuit, thereby being supplied with power from the power supply.
Preferably, the power control system further comprises a voltage detection switch connected between the voltage detection output circuit and the driving coil for detecting the level of the AC voltage, and for allowing power to be supplied to the driving coil when the level of the AC voltage is greater than a predetermined level.
The microcomputer turns off the off mode switch in the off mode so as to cut off the power supply to the driving coil.
According to another aspect of the present invention, these and other objects may also be achieved by provision of a power control method for a display apparatus which comprises a reactor, including a pair of inductors, for calibrating a power factor of an AC voltage supplied from the outside, a rectifier for rectifying the AC voltage having the power factor calibrated by the reactor, a power supply for outputting the rectified voltage with a plurality of voltage levels so as to allow them to be supplied to a power-consuming component, and a switch unit for connecting the pair of inductors in series or in parallel based on a driving power corresponding to the level of the AC voltage supplied to the reactor. The method comprises the steps of determining whether a DPMS is in an off mode so as to cut off the power supply to each component, and cutting off the power supply to the switch unit in the off mode.
Preferably, the power control method further comprises the steps of detecting the level of the AC voltage supplied to the reactor, and supplying power to the switch unit if the detected level of the AC voltage is greater than a predetermined level.
It is also preferable that the power control method further comprise the steps of connecting the switch unit to an output terminal of the power supply so as to allow it to be supplied with power from the power supply, and mounting an off mode switch at the output terminal of the power supply so as to cut off the power supplied by the power supply. In the step of cutting off the power supply to the switch unit in the off mode, the off mode switch is turned off.